For my taste, this band is just not my style. I can see this being very useful for some as watch batteries are crap. At least my Samsung Gear S3 Frontier needed recharging every day. I returned it to Best Buy.

Right now my Apple Watch get recharge every 2 days, I wanted to start tracking my sleeping pattern so I staterted wearing the watch when I sleep. The charge work around for me is that I have 20 min commute from and to work, I charge the watch while I drive, that will give around 40% each way. I think that battery pack will be a very specific scenario. Not for me at least.